netdev - [PATCH 03/12] flow_dissector: Move ETH_P

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Message-Id: <20240731172332.683815-4-tom@herbertland.com>
Date: Wed, 31 Jul 2024 10:23:23 -0700
From: Tom Herbert <tom@...bertland.com>
To: davem@...emloft.net,
	kuba@...nel.org,
	edumazet@...gle.com,
	netdev@...r.kernel.org,
	felipe@...anda.io
Cc: Tom Herbert <tom@...bertland.com>
Subject: [PATCH 03/12] flow_dissector: Move ETH_P_TEB out of GRE

If the GRE protocol is ETH_P_TEB then just process that as any
another EtherType since it's now supported in the main loop

Signed-off-by: Tom Herbert <tom@...bertland.com>
---
 net/core/flow_dissector.c | 36 ++++++++++--------------------------
 1 file changed, 10 insertions(+), 26 deletions(-)

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index d9abb4ae021b..416f889c623c 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -654,7 +654,7 @@ __skb_flow_dissect_gre(const struct sk_buff *skb,
 		       struct flow_dissector_key_control *key_control,
 		       struct flow_dissector *flow_dissector,
 		       void *target_container, const void *data,
-		       __be16 *p_proto, int *p_nhoff, int *p_hlen,
+		       __be16 *p_proto, int *p_nhoff, int hlen,
 		       unsigned int flags)
 {
 	struct flow_dissector_key_keyid *key_keyid;
@@ -663,7 +663,7 @@ __skb_flow_dissect_gre(const struct sk_buff *skb,
 	u16 gre_ver;
 
 	hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr),
-				   data, *p_hlen, &_hdr);
+				   data, hlen, &_hdr);
 	if (!hdr)
 		return FLOW_DISSECT_RET_OUT_BAD;
 
@@ -695,7 +695,7 @@ __skb_flow_dissect_gre(const struct sk_buff *skb,
 
 		keyid = __skb_header_pointer(skb, *p_nhoff + offset,
 					     sizeof(_keyid),
-					     data, *p_hlen, &_keyid);
+					     data, hlen, &_keyid);
 		if (!keyid)
 			return FLOW_DISSECT_RET_OUT_BAD;
 
@@ -715,27 +715,11 @@ __skb_flow_dissect_gre(const struct sk_buff *skb,
 	if (hdr->flags & GRE_SEQ)
 		offset += sizeof_field(struct pptp_gre_header, seq);
 
-	if (gre_ver == 0) {
-		if (*p_proto == htons(ETH_P_TEB)) {
-			const struct ethhdr *eth;
-			struct ethhdr _eth;
-
-			eth = __skb_header_pointer(skb, *p_nhoff + offset,
-						   sizeof(_eth),
-						   data, *p_hlen, &_eth);
-			if (!eth)
-				return FLOW_DISSECT_RET_OUT_BAD;
-			*p_proto = eth->h_proto;
-			offset += sizeof(*eth);
-
-			/* Cap headers that we access via pointers at the
-			 * end of the Ethernet header as our maximum alignment
-			 * at that point is only 2 bytes.
-			 */
-			if (NET_IP_ALIGN)
-				*p_hlen = *p_nhoff + offset;
-		}
-	} else { /* version 1, must be PPTP */
+	/* For GRE version 0 p_proto is already correctly set (including if
+	 * it is ETH_P_TEB)
+	 */
+
+	if (gre_ver == 1) { /* Version 1 is PPP */
 		u8 _ppp_hdr[PPP_HDRLEN];
 		u8 *ppp_hdr;
 
@@ -744,7 +728,7 @@ __skb_flow_dissect_gre(const struct sk_buff *skb,
 
 		ppp_hdr = __skb_header_pointer(skb, *p_nhoff + offset,
 					       sizeof(_ppp_hdr),
-					       data, *p_hlen, _ppp_hdr);
+					       data, hlen, _ppp_hdr);
 		if (!ppp_hdr)
 			return FLOW_DISSECT_RET_OUT_BAD;
 
@@ -1552,7 +1536,7 @@ bool __skb_flow_dissect(struct net *net,
 
 		fdret = __skb_flow_dissect_gre(skb, key_control, flow_dissector,
 					       target_container, data,
-					       &proto, &nhoff, &hlen, flags);
+					       &proto, &nhoff, hlen, flags);
 		break;
 
 	case NEXTHDR_HOP:
-- 
2.34.1